Manufacture of soap



PATENT OFFICE.

MARTIN HILL I'ITNER, 0F JERSEY CITY, NEW JERSEY.

MANUFACTURE OF SOAP.

No Drawing.

1 0 all whom it may concern Be it known that I, MAn'rix HILL ITTNER, a citizen of the United States, residing at Jersey City, county of Hudson, State of New Jersey, have invented. certain new and useful lmproven'ients in the Manufacture of Soap; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a method of producing soaps which has the advantage over methods heretofore commonly practised that it enables a more effective removal of impurities and accomplishes a very material saving in time over that requisite to produce soaps of the same kind by the Well known methods now in use.

The invention is based upon the discovery that certain stages, hereinafter specified, of the processes for making soap, dependent upon standing and ordinary gravity settling, may be greatly hastened and mproved by the use of centrifugal act on. The invention is characterized by a saving in time so considerable, as compared with the common methods of gravity settling and separation, that a factory operating in accordance with the present invention Wlll have a very much larger capacity than one operating under the processes commonly used. So also, a factory operating 1n accordance with the present invention and having the same capacity as one operating under the common methods now utilized, can be much smaller than is at present necessary.

In practising the invention, soap is first produced by one of the common and well known methods, for example; by the saponification of fats or oils or fat-like bodies with alkaline agents; or by the action of alkali or alkaline carbonates on fatty acids or acids resembling fatty acids in their property of forming soaps; or by the double decomposition of alkaline salts and soaps of other metals, such as the action of sodium carbonate on lime soap, etc. Such soaps have the property of being much less soluble in lyes, (such as solutions of caustic soda), or in salt solutions, (such as solutions of common salt), than they are in water alone. Accordingly, by adding to such soaps or soap solutions, salts or salt solutions, or alkalis or lyes, the soap partially or almost completely segregates out and separates in Specification of Letters Patent.

Patented Feb. 8, 1921.

Application fi1ed"'May 8, 1916. Serial No. 96,113.

the form of curds from the solution which may then he removed. This aqueous solution o r layer removes with it some of the impurities and it may be used for the recovery of the glycerin contained in it which s formed when fats and fatty oils containing glycerids are made into soap.

The soap thus segregated and separated from the lyes or salt solutions is in the form of curds. The separation of the aqueous layer orspent lye or salt solutions from the soap 1s commonly effected by gravity settling. In this condition, the soap or soap curds are heavy so that they will not flow as a thin liquid. For this reason, such soap does not lend itself readily to any continu' ous mechanical method of separation.

Soap which has been completely or partially separated from solution of lye or salts and from which the separated solution of lye or salts has been removed, may be made into settled soap. By this process, the curd soap freed from the spent lye is heated and agitated, preferably with open steam, water being added when necessary in addition to that formed from the condensed steam to so dilute the lye still adhering to the soap curds as to cause the curds to flow together and the whole mass to become very much thinner in consistency. When this point is reached and the agitation stopped, the soap will, if the temperature is maintained a little short of the boiling point, separate after long standing into two layers, the lower or nigre being a strong solution of soap in dilute lye and the upper a layer of settled soap containing a small amount of dissolved lye.

l have found that the soap in the condition described lends itself readily to continuous mechanical separation into two liquid layers. Continuous mechanical separation is of particular advantage for the reason, among others, that the settled soap and nigre layers are forced to rearrange themselves under the centrifugal action whereby the heavier nigre is forced to the periphery of the machine and the lighter settled soap forced inwardly nearer the center of the machine.

The separation in a continuous manner, by the use of a continuously operating centrifugal separator of appropriate construction. has the further important advantage, that, by its use, large charges of soap such as are produced in soap kettles. can he passed rapidly, and in a continuous manner,

through the centrifugal machine. Thus, large batches of soap can be separated in a continuously operating centrifugal machine of relatively small size, in a sufficiently rapid manner to permit separation of the whole charge even at the boiling te1nperature and in any event before it has cooled below the temperature at which the desired separation is most complete.

I By the old gravity settling process, the settling docs not begin at once on removing the source of heat, owing to the strong convection currents in the hot soap that retard separation. Later, as these currents become less marked, owing to the" cooling of the soap, the settling becomes more and more retarded, owing to the gradual stiffening of the soap due to cooling. The ordinary gravity settling, furthermore, does not remove much of the fine dirt or insoluble impurities and is less effective in removing the soluble impurities; considerable time being always required, amounting, for large batches, to as much as a week or more.

According to the present invention, the soap, after the addition of sufficient water to make it thin enough to flow freely as above described, is subjected to the centrifugal separating action and effectively separated into two layers, one of pure settled soap, and one of nigre containing almost all of the soluble'impurities not removed by the lyes previously separated from the soap curds. At the same time, much dirt or other insoluble matter not removed by gravity settling is thrown to the extreme periphery of the rapidly revolving centrifugal machine, thereby brightening up the soap appreciably.

As noted above, it is of particular advantage to effect the centrifugal separation in a continuous manner, for the reason that large batches of soap can be run through the machine in a relatively short period of time and the separation of the soap and aqueous liquor continuously effected therein. As a result of the centrifugal action continuously going on during the separation, the soap and aqueous liquor are caused to separate from each other so that the liquor and the soap will be discharged relatively free from each other and in a continuous manner. .The hot pure settled soap is removed in liquid form from the hot solution of soap in lye or nigre, the nigre, containing the soluble impurities. Moreover, the separation is thus effected at once while the soap is hottest and thinnest and most inclined to separate, the

continuous separation permitting the treatment of relatively large batches of soap in centrifugal machines of small size in relatively short periods of time while the soap is still hot and its separation readily effected.

separation is effected, in a short pcriodbf time, and while the soap is still hot or even near the boiling point.

The impure soap or nigre obtained by the centrifugal separation, may be promptly subjected to treatment with salt, salt solutions or lye,-and again subjected to centrifugal separation, while still hot, whereby the greater portion of the soap contained therein is separated from most of its impurities.

The purer portion of soap, from which the nigre has been separated in the manner indicated above, may be put into frames or molds and allowed to cool therein, by the action of the air, water, or other cooling medium, or the hot purified soap may be rapidly cooled by the action of air or water or other cooling medium, for example, by exposing it in film form to cooling and drying, whereby the soap may be obtained in a pure dried, solid form, suitable for. making milled soaps.

I claim 1. The method of effecting the separation of settled soap from strong solutions of soap in dilute lye, which comprises subjecting the same, while .in a thin freely flowing condition, to a continuous centrifugal separation; substantially as described.

2. The method of effecting the separation of settled soap from strong solutions of soap in dilute lye, which comprises subjecting the same, while in a thin freely flowing condition, to centrifugal action in a continuously operating centrifugal separator, whereby the settled soap and soap solution are separately obtained in a' continuous manner and while still in a highly heated condition; substantially as described. I

3. The method of effecting the separation of soap from impurities, which comprises separating the soap from most of the lye, adding water to the separated soap and heating the .same to form a thin, freely flowing liquor, and subjecting such liquor to centrifugal action and thereby effecting the separation of the soap into soaps of two different degrees of purity; substantially as described.

4. The method of effecting the separation of soap from impurities, which comprises separating the soap from most of the lye, adding water to the separated soap and heating the same to form a thin, freely flowing liquor, and subjecting such liquor to a continuous centrifugal separation and thereby separating the soap into soaps of two dlfferent degrees of purity and obtaining these soaps in a continuous manner; substantially as described.

In testimony whereof I affix my signature.

MARTIN HILL ITTNER. 

